Radio transmission relay stations



y 1966 JEAN-CLAUDE SIMON ET AL 3,263,229

RADIO TRANSMISSION RELAY STATIONS Filed Sept. 12, 1962 2 Sheets-Sheet l FIG-1 FIG.2

July 26, 1966 JEAN-CLAUDE SIMON ET AL 3,263,229

RADIO TRANSMISSION RELAY STATIONS Filed Sept. 12, 1962 2 Sheets-Sheet 2 United States Patent "ice 2 Claims. (a. 343-100 The present invent-ion relates to radio link relay stations, of the type described in the copending patent application Serial No. 163,184, now Patent No. 3,188,640, filed by the applicants in the United States Patent Ofiice December 29, 1961, and assigned to the same assignee.

The radio link relay for artificial satellites described in above mentioned copending application, is provided with a plurality of directional antennas positioned in such a manner that, for any orientation of the satellite, the communication can be received from any given point of the terrestrial globe viewed from the satellite and retransmitted towards another such point. The described relay presents, however, the drawback of making a substantial number of antennas necessary, this number being all the greater as their directivity is higher,

The invention relates more particularly to satellites, which are launched from points located in the vicinity of the Equator and follow orbits situated in the equatorial plane of the terrestrial globe. As is known, such satellites may be stabilized by comparatively simple means, to keep constantly their axis parallel to the polar axis of the globe. Such means are known in the art. It is possible with available launching vehicles, to launch a satellite spinning about the axis of greatest moment of inertia, and with this axis normal to the plane of the desired orbit. In this way, the vehicle will tend to continue, in orbit, the spin axis always normal to this plane.

The relay according to the invention is particularly adapted to equip satellites of this latter type, the fact that such satellites are stabilized as indicated making it possible to reduce the number of the antennas of the relay. It comprises a plurality of directive antennas, equally spaced from each other and arranged along the equatorial plane of the satellite, the radiation patterns of the adjacent aerials overlapping at a level 3 db below the maximum and their aperture angles in the equatorial plane being at this level substantially equal to the angle within which the Equator -is seen from the satellite.

The invention will be best understood from the following description and appended drawings, wherein:

FIGS. 1 and 2 are respectively plane and elevation views of a satellite provided with a relay according to the invention; and

FIGS. 3 and 4 are explanatory diagrams.

FIGS. 1 and 2 represent a spherical satellite 1. It is assumed that, as indicated above, the axis n-s of the satellite is maintained parallel to the polar axis of the earth, while it describes, as shown in FIG. 3, an orbit O in the equatorial plane of the globe.

Directional antennas 2 are disposed on the satellite and supported on a suitable surface. These antennas are in the equatorial plane of the satellite which is perpendicular to line n-s. These antennas are equally spaced along the equatorial line of the satellite. Their radiation patterns have in the equatorial plane such an aperture that they overlap each other at a level 3 db below the maximum and the number of antennas is such that, in the whole of the equatorial plane, the radiation is always at a level which is never lower than 3 db below the maximum.

3,263,229 Patented July 26, 1966 The aperture a corresponding to a radiation level 3 db below the maximum depends on the distance from the satellite to the earth. Aperture at will be selected equal to the mean angle under which the earth is viewed from satellite 1.

It may be readily seen that with a satellite such as that considered the number of antennas required for insuring the communication between the satellite and the earth is twice lower than in the case of a satellite which is not stabilized at all. This number is 21/9 instead of 41r/Q, 9 being the solid angle within which each directional antenna used has the desired radiation intensity.

The aperture of the radiation lobe in the meridian plane common to the earth and to the satellite is determined by the zone of the earths surface to be covered and is not necessarily the same as the equatorial plane.

FIG. 4 is a cross-section though the meridian plane common to the satellite and earth.

The axis of the radiation cone is, as shown, inclined at an angle a to the equatorial plane A-A.

The aperture of the cone is such that the radiation is concentrated in an equatorial region, the poles N and S not being illuminated.

The structure of the aerials and the switching system is the same as that described in the above mentioned copending patent application.

Of course, the invention is not limited to the embodiment described which is given solely by way of example.

What is claimed is:

1. A radio link relay for ultra short waves, for an artificial satellite launched from a point located in the vicinity of the Equator, following orbits situated in the equatorial plane of the terrestrial globe and having stabilizing means to keep constantly its axis parallel to the polar axis of the globe, said relay comprising a plurality of directive simultaneously transmitting and receiving antennas, equally spaced from each other and all arranged in the equatorial plane of the satellite, said aerials having respective radiation patterns overlapping each other in said equatorial plane at a predetermined level below their maximum level, the aperture angle of said patterns being equal to the angle under which the terrestrial globe is viewed from the satellite.

2. A radio link relay for ultra short waves, for an artificial satellite launched from a point located in the vicinity of the Equator following orbits situated in the equatorial plane of the terrestrial globe and having stabilizing means to keep constantly its axis parallel to the polar axis of the globe, said relay comprising a plurality of directive simultaneously transmitting and receiving antennas, equal- 1y spaced from each other and all arranged in the equatorial plane of the satellite, said aerials having respective radiation patterns overlapping each other in said equatorial plane, at three db below their maximum level, the aperture angle of said pattern being equal to the average angle under which the earth is seen from the satellite.

References Cited by the Examiner UNITED STATES PATENTS 3,063,048 11/1962 Lehan et al. 343- 3,095,538 6/1963 Silberstein 343100 3,100,892 8/1963 Cutler 343--100 3,132,342 5/1964 Ford 343-400 CHESTER L. IUSTUS, Primary Examiner.

M. KRAUS, E. T. CHUNG, R. E. BERGER,

Assistant Examiners. 

1. A RADIO LINK RELAY FOR ULTRA SHORT WAVES, FOR AN ARTIFICIAL SATELLITE LAUNCHED FROM A POINT LOCATED IN THE VICINITY OF THE EQUATOR, FOLLOWING ORBITS SITUATED IN THE EQUATORIAL PLANE OF THE TERRESTRIAL GLOBE AND HAVING STABILIZING MEANS TO KEEP CONSTANTLY ITS AXIS PARALLEL TO THE POLAR AXIS OF THE GLOBE, SAID RELAY COMPRISING A PLURALITY OF DIRECTIVE SIMULTANEOUSLY TRANSMITTING AND RECEIVING ANTENNAS, EQUALLY SPACED FROM EACH OTHER AND ALL ARRANGED IN THE EQUATORIAL PLANE OF THE SATELLITE, SAID AERIALS HAVING RESPECTIVE RADIATION PATTERNS OVERLAPPING EACH OTHER IN SAID EQUATORIAL PLANE AT A PREDETERMINED LEVEL BELOW THEIR MAXIMUM LEVEL, TE APERTURE ANGLE OF SAID PATTERNS BEING EQUAL TO THE ANGLE UNDER WHICH THE TERRESTRIAL GLOBE IS VIEWED FROM THE SATELLITE. 